In a plasma etching method for forming a hole in an etching target film, a process of generating a plasma of a processing gas containing at least CxFy gas and a rare gas having a mass smaller than a mass of Ar gas into the processing chamber in the processing chamber by switching on a high frequency power application unit under a first condition and a process of extinguishing the plasma of the processing gas in the processing chamber by switching off the high frequency power application unit under a second condition are alternately repeated. A negative DC voltage from a DC power supply is applied such that an absolute value of the negative DC voltage of the second condition becomes greater than an absolute value of the negative DC voltage of the first condition.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A plasma etching method for forming a hole in an etching target film by using a plasma etching apparatus including: an evacuable processing chamber configured to accommodate a processing target object; a lower electrode, provided in the processing chamber, serving as a mounting table for the processing target object; an upper electrode provided in the processing chamber to face the lower electrode; a processing gas supply unit configured to supply a processing gas containing at least C x F y gas and a rare gas having a mass smaller than a mass of Ar gas into the processing chamber; a high frequency power application unit configured to apply a high frequency power for plasma generation to at least one of the upper electrode and the lower electrode; and a DC power supply configured to apply a negative DC voltage to the upper electrode, the method comprising: etching the etching target film to form a hole therein by alternately repeating a process of generating a plasma of the processing gas supplied into the processing chamber by switching on the high frequency power application unit under a first condition and a process of extinguishing the plasma of the processing gas in the processing chamber by switching off the high frequency power application unit under a second condition, and applying the negative DC voltage from the DC power supply such that an absolute value of the negative DC voltage of the second condition becomes greater than an absolute value of the negative DC voltage of the first condition.
2. A plasma etching method for forming a hole in a first insulating layer and a second insulating layer by using a plasma etching apparatus including: an evacuable processing chamber configured to accommodate a processing target object having a laminated film obtained by alternately laminating a first insulating layer and a second insulating layer and a mask layer formed on the first insulating layer; a lower electrode, provided in processing chamber, serving as a mounting table for the processing target object; an upper electrode provided in the processing chamber to face the lower electrode; a processing gas supply unit configured to supply a processing gas containing at least a C x F y gas and a rare gas having a smaller mass than a mass of Ar gas into the processing chamber; a high frequency power application unit configured to apply a high frequency power for plasma generation to at least one of the upper electrode and the lower electrode; and a DC power supply for applying a negative DC voltage to the upper electrode, the method comprising: a first plasma etching step of etching the first insulating layer by a first plasma; and a second plasma etching step of etching the second insulating layer by a second plasma, wherein the second plasma etching step includes: etching the second insulating layer to form a hole therein by alternately repeating a process of generating a plasma of the processing gas supplied into the processing chamber by switching on the high frequency power application unit under a first condition and a process of extinguishing the plasma of the processing gas in the processing chamber by switching off the high frequency power application unit under a second condition, and applying the negative DC voltage from the DC power supply such that an absolute value of the negative DC voltage of the second condition becomes greater than an absolute value of the negative DC voltage of the first condition.
3. The plasma etching method of claim 1 , wherein the C x F y gas is C 4 F 6 gas or C 4 F 8 gas, and the processing gas contains at least one of the C 4 F 6 gas and the C 4 F 8 gas.
4. The plasma etching method of claim 2 , wherein the C x F y gas is C 4 F 6 gas or C 4 F 8 gas, and the processing gas contains at least one of the C 4 F 6 gas and the C 4 F 8 gas.
5. The plasma etching method of claim 1 , wherein the processing gas further contains O 2 gas.
6. The plasma etching method of claim 2 , wherein the processing gas further contains O 2 gas.
7. The plasma etching method of claim 1 , wherein the processing gas further contains NF 3 gas.
8. The plasma etching method of claim 2 , wherein the processing gas further contains NF 3 gas.
9. The plasma etching method of claim 1 , wherein a rare gas having a mass smaller than a mass of the Ar gas is He gas or Ne gas.
10. The plasma etching method of claim 2 , wherein a rare gas having a mass smaller than a mass of the Ar gas is He gas or Ne gas.
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March 4, 2015
April 26, 2016
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